What is the difference between Babyliss Big Hair and a Sheer Volume?

[MrsFogi]

The question says it all really - as a result of reading mn too much and my inability to control a hairdryer, brush and hair simultaneously I am going to succumb to one of these but am a bit lost about the difference between the Big Hari and Sheer Volume.

BBH blows air, sheer volume just heats. Don’t ask me what the practical difference is tho...
The sheer volume is touted as something that can be used on dry hair as well, which the BBH isn’t.
If you find out what the difference means in practice, let me know!
I do love my BBH tho because I am seriously cack handed.

Bbh is used on wet hair. Sheer volume is used on dry hair.

Bbh gives the effect of a good blow dry. Sheer volume gives an effect similar to a straightener except without the blunt ends.

They look similar but they're actually plenty different.